Rivnut help: nosepieces keep breaking off

[musigenesis]

I bought a rivnut kit from Amazon and tried it out today for the first time. My first attempt was with a 10-24 rivnut and I broke the nosepiece. Then I tried to set one of the closed-end 1/4-20 rivnuts and that went in and crimped perfectly. Then on the second 1/4-20 I broke that nosepiece as well so now I'm SOL.

What am I doing wrong? I think it's to do with setting the proper stroke length but I can't find any info on how to do that (my setter came with a manual that only appears to be in English).

 

[o1marc]

I bought a rivnut kit from Amazon and tried it out today for the first time. My first attempt was with a 10-24 rivnut and I broke the nosepiece. Then I tried to set one of the closed-end 1/4-20 rivnuts and that went in and crimped perfectly. Then on the second 1/4-20 I broke that nosepiece as well so now I'm SOL.

What am I doing wrong? I think it's to do with setting the proper stroke length but I can't find any info on how to do that (my setter came with a manual that only appears to be in English).

Is yours setting the nut with one squeeze? On Mine you squeeze, screw the mandrel in deeper and squeeze until you feel it is snug, past that and it snaps the mandrel end off. Thread the nut sert onto the mandrel till it's seated, insert in hole and squeeze the handels, readjust , squeeze, remove tool.

 

[musigenesis]

Is yours setting the nut with one squeeze? On Mine you squeeze, screw the mandrel in deeper and squeeze until you feel it is snug, past that and it snaps the mandrel end off. Thread the nut sert onto the mandrel till it's seated, insert in hole and squeeze the handels, readjust , squeeze, remove tool.

I think I went "past that" for sure. The one that worked, I pulled it a bit then redialed and pulled again, never getting all the way to where the arms came together. The failed one I just went all the way until it snapped.

I'm going to try this method now since I'm out of mandrels:

. Seems like maybe I'll be able to control this better - my setter has 16" arms and these 1/4-20 closed rivnuts are fairly tough.

 

[o1marc]

I think I went "past that" for sure. The one that worked, I pulled it a bit then redialed and pulled again, never getting all the way to where the arms came together. The failed one I just went all the way until it snapped.

I'm going to try this method now since I'm out of mandrels:

. Seems like maybe I'll be able to control this better - my setter has 16" arms and these 1/4-20 closed rivnuts are fairly tough.

I don't think you'll ever sink the second pull. Just squeeze till it's snug. Live and learn. When mine got tight, I knew what the next outcome would be.

 

[alpine44]

I bought a rivnut kit from Amazon and tried it out today for the first time. My first attempt was with a 10-24 rivnut and I broke the nosepiece. Then I tried to set one of the closed-end 1/4-20 rivnuts and that went in and crimped perfectly. Then on the second 1/4-20 I broke that nosepiece as well so now I'm SOL.

What am I doing wrong? I think it's to do with setting the proper stroke length but I can't find any info on how to do that (my setter came with a manual that only appears to be in English).

I you squeeze past snug, you will either snap the threaded mandrel or strip the threads out of the rivnut. 'Snug' means that you feel a greatly increased resistance. At this point, the back of the rivnut is fully bulged and there is no need to go any further.

There are two ways to avoid the rivnut spinning in the hole (and over-squeezing is not one of them).

Some rivnuts have a serrated collar just under the flange. The drilled hole needs to be small enough for these serrations to engage in the base metal.

Other rivnuts have a 'key' swaged into the flange and you need to file a small cutout into the drilled hole. With the right file, that just takes one or two strokes.

 

[musigenesis]

I you squeeze past snug, you will either snap the threaded mandrel or strip the threads out of the rivnut.
'Snug' means that you feel a greatly increased resistance. At this point, the back of the rivnut is fully bulged and there is no need to go any further.

The back wasn't bulged at all when the mandrel snapped. The first one I did (that didn't snap the mandrel) had a very nice bulge on the back and the grip was very solid.

I just tried out using a bolt with a nut and two wrenches but I snapped the head off the bolt - cheapie bolts won't do the trick here, I guess.

 

[alpine44]

The back wasn't bulged at all when the mandrel snapped. The first one I did (that didn't snap the mandrel) had a very nice bulge on the back and the grip was very solid.

I just tried out using a bolt with a nut and two wrenches but I snapped the head off the bolt - cheapie bolts won't do the trick here, I guess.

If the base metal is way too thick, then the rivnut cannot bulge. The other possibility is that the rivnuts you are using are out of spec.

I see that your are living in Philly. You could drive to Wings Field in Blue Bell and have one of the aircraft shops show you the right rivets, tools, and procedure.

Here is the key (in the 1 o'clock position) I was talking about earlier.

The rivnut shown is for a #6 screw to hold non-structural item like inspection plates, etc. and requires a very gentle touch to not strip it out during the swaging process.

 

[musigenesis]

If the base metal is way too thick, then the rivnut cannot bulge. The other possibility is that the rivnuts you are using are out of spec.

I see that your are living in Philly. You could drive to Wings Field in Blue Bell and have one of the aircraft shops show you the right rivets, tools, and procedure.

Here is the key (in the 1 o'clock position) I was talking about earlier.

View attachment 37542The rivnut shown is for a #6 screw to hold non-structural item like inspection plates, etc. and requires a very gentle touch to not strip it out during the swaging process.

I got the bolt and nut method to work - my problem was I was using a threaded nut which can't produce any other outcome than a stripped bolt head. It's too difficult to control both wrenches by myself and keep the rivnut properly positioned, though, so I ordered a couple more 1/4-20 mandrels.

I wonder if I'm overestimating their structural strength, though. I'm using these rivnuts for the four holes for each 7" light on the back of my bus. The metal there is kind of bent and floppy, so I've placed a piece of 1/8" steel behind the lights and I am attempting to use the rivnuts both to attach the lights and to hold this piece on the inside. The pieces I've been testing out my rivnuts on are the same thickness (1/8' + 16 ga) and they do bulge properly (they're specced for the thickness I'm going through).

Should I also attach this plate with screws or regular rivets?

 

[alpine44]

I got the bolt and nut method to work - my problem was I was using a threaded nut which can't produce any other outcome than a stripped bolt head. It's too difficult to control both wrenches by myself and keep the rivnut properly positioned, though, so I ordered a couple more 1/4-20 mandrels.

I wonder if I'm overestimating their structural strength, though. I'm using these rivnuts for the four holes for each 7" light on the back of my bus. The metal there is kind of bent and floppy, so I've placed a piece of 1/8" steel behind the lights and I am attempting to use the rivnuts both to attach the lights and to hold this piece on the inside. The pieces I've been testing out my rivnuts on are the same thickness (1/8' + 16 ga) and they do bulge properly (they're specced for the thickness I'm going through).

Should I also attach this plate with screws or regular rivets?

Unless you have to thread a screw/bolt in the hole after joining the metals sheets, I would use anything but rivNUTS. They are designed as nuts for places where limited access does not allow the use of nut plates (a nut on a plate that is riveted to the base metal) let alone regular nuts.

 

[musigenesis]

Unless you have to thread a screw/bolt in the hole after joining the metals sheets, I would use anything but rivNUTS.

Well, that's why I'm using rivnuts. But I'm wondering if, since I'm already using rivnuts for the light screws (12 for each plate, essentially), I can rely on those 12 rivnuts to hold the plate on the inside adequately.

I think I will also add some bolts/nuts to hold the plate on independently of the rivnuts.